Mercarb Marine Jet Sizes
Find your current jet size by inspecting your main jet. It will be stamped with 3 numbers. A 165 indicates a 1.65 mm jet.
Model
Carburetor Numbers
0-5000 ft
5000 ft +
25L/3.0L OC856400 and below
1389-9562A, 3310-806077A, 3310-860070A
1.45 mm
1.40 mm
3.0L OC856451-OF353099
1389-815396A, 3310-806078A
1.60 mm
1.50 mm
3.0L OL000001 and above
3310-807504A
1.55 mm
1.55 mm
3.0LX
1389-815397A,
1.65 mm
1.55 mm
3310-805924A
1.60 mm
1.50 mm
3310-807504A
1.55 mm
1.55 mm
4.3L, 4.3LX
1389-9565A4
1.65 mm
1.55 mm
1389-9565A, 3310-806080A, 3310-806972A
1.60 mm
1.50 mm
3310-807764A
1.55 mm
1.45 mm
5.0L
1389-9563A, 3310-806081A, 3310-861080A
1.70 mm
1.60 mm
1389-9670A, 3310-806082A
1.85 mm
1.75 mm
5.7L
3310-807312A, 3310-861245A
1.65 mm
1.50 mm
At the time of this writing Mercarb jets are not available.
What we do when we can’t get jets.
Drill out the jet to a bigger size.
Solder the jet shut, then drill to the size you need.